bk commit into 5.1 tree (anozdrin:1.2546) BUG#31222

[Alexander Nozdrin]

Below is the list of changes that have just been committed into a local
5.1 repository of anozdrin.  When anozdrin does a push these changes
will be propagated to the main repository and, within 24 hours after the
push, to the public repository.
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see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet@stripped, 2008-02-12 20:59:09+03:00, anozdrin@quad. +3 -0
  Fix for Bug#31222: com_% global status counters
  behave randomly with mysql_change_user.
    
  The problem was that global status variables were not updated
  in THD::check_user(), so thread statistics were lost after
  COM_CHANGE_USER.
    
  The fix is to update global status variables with the thread ones
  before preparing the thread for new user.

  mysql-test/r/change_user.result@stripped, 2008-02-12 20:59:08+03:00, anozdrin@quad. +7 -0
    Update result file.

  mysql-test/t/change_user.test@stripped, 2008-02-12 20:59:08+03:00, anozdrin@quad. +28 -0
    Add a test case for Bug#31222: com_% global status counters
    behave randomly with mysql_change_user.

  sql/sql_class.cc@stripped, 2008-02-12 20:59:08+03:00, anozdrin@quad. +4 -0
    Update global status variables when we're handling
    COM_CHANGE_USER for a thread.

diff -Nrup a/mysql-test/r/change_user.result b/mysql-test/r/change_user.result
--- a/mysql-test/r/change_user.result	2007-12-10 10:12:40 +03:00
+++ b/mysql-test/r/change_user.result	2008-02-12 20:59:08 +03:00
@@ -44,3 +44,10 @@ IS_FREE_LOCK('bug31418')
 SELECT IS_USED_LOCK('bug31418');
 IS_USED_LOCK('bug31418')
 NULL
+FLUSH STATUS;
+SHOW GLOBAL STATUS LIKE 'com_select';
+Variable_name	Value
+Com_select	112
+SHOW GLOBAL STATUS LIKE 'com_select';
+Variable_name	Value
+Com_select	112
diff -Nrup a/mysql-test/t/change_user.test b/mysql-test/t/change_user.test
--- a/mysql-test/t/change_user.test	2007-10-17 23:43:26 +04:00
+++ b/mysql-test/t/change_user.test	2008-02-12 20:59:08 +03:00
@@ -33,3 +33,31 @@ SELECT IS_USED_LOCK('bug31418') = CONNEC
 --change_user
 SELECT IS_FREE_LOCK('bug31418');
 SELECT IS_USED_LOCK('bug31418');
+
+#
+# Bug#31222: com_% global status counters behave randomly with
+# mysql_change_user.
+#
+
+FLUSH STATUS;
+
+--disable_result_log
+--disable_query_log
+
+let $i = 100;
+
+while ($i)
+{
+  dec $i;
+
+  SELECT 1;
+}
+
+--enable_query_log
+--enable_result_log
+
+SHOW GLOBAL STATUS LIKE 'com_select';
+
+--change_user
+
+SHOW GLOBAL STATUS LIKE 'com_select';
diff -Nrup a/sql/sql_class.cc b/sql/sql_class.cc
--- a/sql/sql_class.cc	2008-02-09 10:31:19 +03:00
+++ b/sql/sql_class.cc	2008-02-12 20:59:08 +03:00
@@ -769,6 +769,10 @@ void THD::init_for_queries()
 
 void THD::change_user(void)
 {
+  pthread_mutex_lock(&LOCK_status);
+  add_to_status(&global_status_var, &status_var);
+  pthread_mutex_unlock(&LOCK_status);
+
   cleanup();
   killed= NOT_KILLED;
   cleanup_done= 0;